I found this development board on my research and it claimed 32bit adc. Let say voltage around 110V, using this STM32 board and acs712 will this be more accurate? Please comment what you think
no. the problem is that you want measure under 3A with 30A module
List ALL the items you are planning to use AND what you want to measure.An STM32 (3.3volt micro) and and ACS712 (5volt sensor) can't be used together.Don't think you can simply measure complex loads with simple code.Only resistive loads will be 'accurate'.Leo..
Only resistive loads will be 'accurate'.Leo..
Did you read the second sentence of post#17?Forget about the STM32, or forget about the ACS712.
So you don't want to measure current, you only want to detect if the aircon is on.Why don't you use a DS18B20 temp sensor in the air stream.Much safer than fiddling with AC power.Leo..
There are many reasons why you shouldn't use a 5volt ACS712 with a 3.3volt processor.One of them is that the STM32 might not like the possible >=4.5volt output of the sensor.Another one is that you loose ratiometric behaviour. Zero current drift, gain drift, etc.
A clip-on current sensor with 1volt AC output (ebay), with e few extra parts (two resistors + cap), might be a better (and safer) solution for a 3.3volt MCU.Leo..
The Electricity sensor module is a member of Crowtail. It is based on the TA12-200 current transformer which can transform the large AC into small amplitude. You can use it to test large alternating current up to 5A.FeaturesCrowtail compatible interfaceDisplay Type: FSTN/Positive/Transflective/6:00 Visual AngleMaximum 5A inputHigh accuracySmall sizeSpecificationsRatio: 2000: 1Input Current: 0-5AOutput Current: 0-2.5mASampling resistor: 800Sampling voltage: 2VNon-linearity: 0.2%Phase Shift: 5 '
The TA12-100 (200ohm burden resistor) seems to output a peak/peak voltage of 2.8volt@5Amp (1volt AC).Both 5volt and 3.3volt boards should be able to work with that.The TA12-200 outputs 5.6volt peak/peak@5A. Too high for a 3.3volt board.Make sure what you have ordered.Leo..
by resistive load, it means something that generate magnetic field right? i will placing it far from any magnetic field. actually the thing i want to measure is my air conditioner current, when it reach up to 4A i want it to turn on relay to pump water so heat from ourdoor unit get lower. lowering heat means lowering Amp too